A bit of a trivia question here. When you flush a toilet with 'solids'.... normally does that get all the way out to the street sewer mains just with that 1 - 2 flushes / water in the bowl / tank? And about how quickly? The slope is very small, right? Seems to me, a noob, that cast iron is rough inside and for a pipe thats 10 - 20 - 30 years old, so many more rough spots for paper / solids to get hooked on / cause clogs? I've heard that a greater slope is not good, but sewer lines are very gradual per code? And yeah, there's cases (roots, misaligned pipe segments) when clogs do happen. But I'm speaking of a working system. And any idea how long does that take to get out to the street? Not seconds, right? not hours?

I want to had a mixing valve to my indirect got hot water tank. I picked up a watts valve. It says you need to be 12" below the exit of the hot water line out of the tank and have the cold a the bottom, i guess to keep the valve not in the hot water. I never seen it done that way? I draw on the photo how i was going to pipe it. what do you guys think? I could come right out of the tank straight and put in a shutoff and drop down to the mix valve and then tie back into the line before the existing shutoff. If the mixing valve is at the lowest point, do I need to have a drain on the line to drain it out? To install this mixing valve do I need to drain the tank? Is it a good idea? thanks